Structure-activity and immunochemical data provide evidence of developmental- and tissue-specific myosuppressin signaling

► DMS decreased gut motility and cardiac contractility dose dependently. ► Truncated and Y-[Bpa2] DMS analogs were increased agonists in pupal and adult heart. ► Adult, pupal, and larval heart and gut active cores were developmental- and tissue specific. ► Y-[Bpax] DMS activity and binding differed on a developmental- and tissue-specific level. ► DMS-specific antisera stained unique cells and fibers that innervated gut or heart.